ROUTINE FECALYSIS Stool analysis: analysis: is a series of tests done on a stool sample to help diagnose certain conditions affecting the digestive tract, including infection ( such as parasites, viruses, or bacteria ) , poor nutrient absorption or cancer. SPECIMEN COLLECTION Patient education Individuals have limited control in the timing of fecal excretion o Collection is highly undesirable for the patient o Verbal and written instructions should be provided along with the appropriate specimen container o Specimen container Clean, non breakable, sealable and leak proof o Type and amount c ollected o Routine fecalysis: peanut size o Quantitative test(3 day fecal collection): container used is paint cans Contaminants to avoid o Urine: affects detection of protozoa o Tissue paper o Toilet water: contains cleaning agents that affects the chem test) 1. Macroscopic examination Color: o Brown -normal color (bilirubin) o Green - diet, antibiotics (biliverdin) o Black - GI (upper), charcoal, drugs o Red - GI (lower), drugs Consistency: o Formed- normal o Hard - constipation (scybala) o Soft - increased fecal content o Watery - diarrhea, steatorrhea Mucus: Normally not present o If present may indicate: straining during bowel movements , other GIT diseases o 2. Microscopic examination Blood streaks and undigested food - if observed, report as PRESENT Parasites - if none, report as none seen Fecal fat o Fecal stains: Sudan III, Sudan IV, Oil Red O ( neutral fat - triglycerides) Fecal leukocytes and rbc o Normally not present o (+) - invasive/inflammatory, involvement of intestinal wall PROCEDURE: Emulsify stool in NSS approx diameter of 25 centavo pc. o A good preparation: a density such that newsprint could be read if place under the slide o
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Make another wet mount using Lugol's iodine. (Examine for parasites). Do not air dry.
NORMAL FECES Brown, soft, well formed NO blood, pus, bacteria, viruses, fungi, parasites Tubular shape or cylindrical ( reflecting passage through colon) Ph 6 <2 mg/g of sugars called reducing factors are present in stools Increased volume of stool - poor absorption of fats ■
ABNORMAL FECES Blood, pus, mucus, bacteria, virus, parasites PRESENT High levels of fat - chronic pancreatitis, sprue (celiac disease), cystuc fibrosis, others Undigested meat fibers - pancreatitis > 6.8 ph - poor absorption of carbohydrates or fat, and problems with amount of bile in digestive tract < 5.3 ph -poor absorption of sugars Low level of enzyme ( trypsin or elastase) - -digestive complication of pancreas, problem conditions (cystic fibrosis) Blood - bleein g indigestive tract Wbc - bacterial diarrhea. High level of reducing factor - problem digesting certai sugar (esp sucrase and lipase) Low level reducing factor - sprue, CF, malnutrition Medications ( colchine - for gout) or oral c ontraceptive may cause low levels o ■
CHEMICAL TEST: FOBT (FECAL OCCULT BLOOD TEST) Principle: pseudoperoxidase activity of hemoglobin
Indicators: o Benzidine - most sensitive but carcinogenic so no longer used o Orthotolidine- 2nd in sensitivity o Guaiac - least sensitive, INDICATOR OF CHOICE, eliminates false positive caused of dietary factors Factors affecting testing Improper collection o Contamination ( menstrual or hemorrhoidal blood) o Defective guaiac or peroxide developer o Storage of fecal specimen or slides beyond 6 days o False (+) - salicylates and iron supplements False (-) - antacids and ascorbic acid Procedure o (+) - blue color o Accurate or reliable - (+) blue line, (-) no color change o Invalid - - (+)no color, (-) blue o Add 2 drops peroxide developer after placing 2 thick smears of stool from diff parts of the stool.
